T,A,B=map(int,input().split())

def euclid(a,b):
    a,b=max(a,b),min(a,b)
    if a%b==0:
        return b
    else:
        a,b=b,a%b
        return(euclid(a,b))

temp=A*B//(euclid(A,B))


print(-(-T//A)-(-T//B)+(-T//temp))